The title compound, (C8H12NO)2[Co(H2P2O7)2(H2O)2]·2H2O, crystallizes isotypically with its MnII analogue. It consists of alternating layers of organic cations and inorganic complex anions, extending parallel to (100). The complex cobaltate(II) anion exhibits -1 symmetry. Its Co2+ atom has an octahedral coordination sphere, defined by two water molecules in apical positions and two H2P2O72− ligands in equatorial positions. The cohesion between inorganic and organic layers is accomplished by a set of O—H⋯O and N—H⋯O hydrogen bonds involving the organic cation, the inorganic anion and the remaining lattice water molecules.